Agassiz Research and Development Centre, Agriculture and Agri-Food Canada, 6947 Highway 7, Agassiz, British Columbia, V0M 1A0, Canada.
Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, V5A 1S6, Canada.
Environ Entomol. 2022 Oct 21;51(5):980-988. doi: 10.1093/ee/nvac067.
In western North America, sympatric Limonius click beetle species produce limoniic acid [(E)-4-ethyloct-4-enoic acid] as a sex pheromone component (L. canus (LeConte), L. californicus (Mannerheim)) or respond to it as a sex attractant (L. infuscatus (Motschulsky)). We tested the hypothesis that these three congeners maintain species-specificity of sexual communication through nonoverlapping seasonal occurrence and/or contrasting diel periodicity of sexual communication. Using capture times of beetles in pheromone-baited traps as a proxy for sexual communication periods, our data show that L. canus and L. californicus have seasonally distinct communication periods. Most L. canus males (>90%) were captured in April and most L. californicus males (>95%) were captured in May/June/July. As almost exclusively L. infuscatus males were captured in two separate 24-hr trapping studies, with data recordings every hour, it remains inconclusive whether the three Limonius congeners communicate at different times of the day. Males of L. infuscatus responded to pheromone lures only during daytime hours and during the warmest period each day. Captures of L. infuscatus overlapping with those of L. canus in April and those of L. californicus in May/June imply the presence of reproductive isolating mechanisms other than seasonal separation of sexual communication periods.
在北美西部，共生的 Limonius 叩头虫物种会产生 limoniic 酸 [(E)-4-ethyloct-4-enoic acid] 作为性信息素成分（L. canus (LeConte)、L. californicus (Mannerheim)），或对其作为性引诱剂做出反应（L. infuscatus (Motschulsky)）。我们测试了以下假设：这三个近缘种通过季节性出现和/或性通讯的昼夜节律的对比来维持性通讯的种间特异性。使用诱捕器中甲虫的捕获时间作为性通讯期的替代指标，我们的数据表明 L. canus 和 L. californicus 的通讯期具有季节性差异。大多数 L. canus 雄性 (>90%) 在四月被捕，大多数 L. californicus 雄性 (>95%) 在五月/六月/七月被捕。由于几乎只有 L. infuscatus 雄性在两项单独的 24 小时诱捕研究中被捕，且每小时都有数据记录，因此尚不清楚这三个 Limonius 近缘种是否在一天中的不同时间进行通讯。L. infuscatus 雄性仅在白天和每天最热的时间段对性信息素诱饵做出反应。四月 L. infuscatus 与 L. canus 的重叠捕获，以及五月/六月 L. californicus 的重叠捕获，意味着存在生殖隔离机制，而不仅仅是性通讯期的季节性分离。
